Ua kapa ʻia ʻo wili kila kila he ʻōwili, ʻōwili mea, ʻōwili pā, ʻōwili pā, me ka paʻakikī nui. Nā hiʻohiʻona kila kila:
1. Nā kikoʻī piha, nā mea like ʻole;
2. Kiʻekiʻe dimensional pololei, a hiki i ± 0.1mm;
3. ʻO ka maikaʻi o ka ʻili maikaʻi, ka mālamalama maikaʻi;
4. Ka ikaika o ka corrosion, ka ikaika tensile kiʻekiʻe a me ka ikaika luhi;
5. Hoʻohui kemika kūpaʻa, kila maʻemaʻe, haʻahaʻa hoʻokomo ʻia;
6. Puke maikai, kumukuai maikai;
7. Hiki ke hana ʻia me ka ʻole calibration.